The effects of three hydration methodologies (carbohydrate, glycerol, and placebo) on the cognitive function of Ss (M = 5; F = 5) during three hours of exercise at 50% VO2max in a heated environment (90 degrees Fahrenheit) were evaluated. A Paced Auditory Serial Addition Task was used to assess cognitive function at three time intervals (5, 80, 175 minutes) of the exercise. The task required Ss to add 61 sets of two single-digit numbers presented on a tape recorder at three increasingly faster speeds (every 2.0, 1.6, and 1.2 seconds).

There were no differences in ratings of perceived exertion or body weight loss between conditions. At the 2.0 and 1.2 speeds of presentation there were no differences between conditions but at 1.6 there was a significant difference favoring carbohydrate ingestion. Blood glucose was significantly higher throughout the complete trial under the carbohydrate condition.

Implication. Cognitive function is enhanced when carbohydrate is ingested as a hydration technique.